mc68hc908qb4 Freescale Semiconductor, Inc, mc68hc908qb4 Datasheet - Page 205

• Manufacturer Part Number: mc68hc908qb4
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

The MCU executes the SWI and PSHH instructions when it enters monitor mode. The RUN command
tells the MCU to execute the PULH and RTI instructions. Before sending the RUN command, the host can
modify the stacked CPU registers to prepare to run the host program. The READSP command returns
the incremented stack pointer value, SP + 1. The high and low bytes of the program counter are at
addresses SP + 5 and SP + 6.
Freescale Semiconductor
Data Returned
Data Returned
Description
Description
Operand
Operand
Opcode
Opcode
Table 17-7. READSP (Read Stack Pointer) Command
Figure 17-17. Stack Pointer at Monitor Mode Entry
Table 17-8. RUN (Run User Program) Command
ECHO
FROM HOST
Reads stack pointer
None
Returns incremented stack pointer value (SP + 1) in high-byte:low-byte
order
$0C
Executes PULH and RTI instructions
None
None
$28
READSP
MC68HC908QB8 Data Sheet, Rev. 2
HIGH BYTE OF PROGRAM COUNTER
LOW BYTE OF PROGRAM COUNTER
HIGH BYTE OF INDEX REGISTER
READSP
LOW BYTE OF INDEX REGISTER
CONDITION CODE REGISTER
ECHO
FROM HOST
Command Sequence
Command Sequence
RUN
ACCUMULATOR
RUN
HIGH
SP
SP
SP + 1
SP + 2
SP + 3
SP + 4
SP + 5
SP + 6
SP + 7
LOW
SP
RETURN
Monitor Module (MON)
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